OBJECTIVE: To determine the association between direct costs for the initial neonatal intensive care unit hospitalization and 4 potentially preventable morbidities in a retrospective cohort of very low birth weight (VLBW) infants (birth weight <1500 g).STUDY DESIGN: The sample included 425 VLBW infants born alive between July 2005 and June 2009 at Rush University Medical Center. Morbidities included brain injury, necrotizing enterocolitis, bronchopulmonary dysplasia, and late-onset sepsis. Clinical and economic data were retrieved from the institution's system-wide data and cost accounting system. A general linear regression model was fit to determine incremental direct costs associated with each morbidity.RESULTS: After controlling for birth weight, gestational age, and sociodemographic characteristics, the presence of brain injury was associated with a $12048 (P = .005) increase in direct costs; necrotizing enterocolitis, with a $15 440 (P = .005) increase; bronchopulmonary dysplasia, with a $31565 (P < .001) increase; and late-onset sepsis, with a $10055 (P < .001) increase. The absolute number of morbidities was also associated with significantly higher costs.CONCLUSION: This study provides collective estimates of the direct costs incurred during neonatal intensive care unit hospitalization for these 4 morbidities in VLBW infants. The incremental costs associated with these morbidities are high, and these data can inform future studies evaluating interventions aimed at preventing or reducing these costly morbidities.